Drill.



PATENTED AUG. 18, 1908.

. W. R. DOWN.

DRILL.

APPLICATION FILED FEB. a, 1908.

Mauro/2 Bios WITNESSES drills are ordinarily held.

.a special chuck is required to grasp the (lllll .UNITE STAES igTEN FFIQE;

\\'ll.l.l.\.\l R. DOWN, OF FLEEIWOOT), PENNSYLVANIA.

DRILL.

Specification of Letters Patent.

Patented Aug. 18, 1908.

Application filed February 3, 1908. Serial No. 413.951..

citizen of theUnited States. residing at Fleet-J wood. in the county of Berks and State of been made in either of the followingways,

viz:--- The drill is made from a solid. cylindrical bar, the th tcs being l'ormed by milling". in this manner about one-half of the material is cut away and as these drills are necessarily made ol very high grade material, the cost of the drills has been neu-ssarily very great. The other method heretofore in use is to take a. flat bar and twist it into the desired shape, leaving the shank end thereof straight but without any suitable shank for engagement by the socket in which these with this method when in use and these chucks have been found unsatisl'actory in that they cannot, by reason of the shape of this end of the drill, hold it snlliciently rigid to bore a hole of the same diameter as that ol' the drill, there being necessarily some morementwhichenlarges the diameter of the hole.

My object in the present instance is to make a drill from a tlat, or substantially flat bar, twisting itinto the desired shape and attaching to the shank end thereof two approximately semi-circular shank. pieces of low grade material, one at either side, thus forming a substantial and practically integral shank that may be held in the ordinary socket. in this manner I sn )ply a. drill of high grade steel with a shaiil of desirable shape at about one-half the cost of those here tol'ore made and one that will still be capable of engagement, with an ordinarysocket.

The invention is more fully described in the following specification and clearly illustrated in the accompanying drawing, in Wliieli:--

Figure 1 is an elevation of my drill complete. Fig. 2 shows the parts about to be assembled. Fig. 3 is a sectional View on line The numeral 1 designates the cutting end of the drill and :2 the shank end. This shank is made up of three parts, namely the central portion 3, being the end of the drill proper and twoside pieces a, eachof which -is substantially semicircular in cross-section and slightly ta )cred to facilitate its engagement in a soccet. These pieces 4 are secured to the body of the drill by rivets, or by brazing or in any other suitable manner and when so attached form substantially an integral part of the drill.

As showm the end portion 2 of the drill projects beyond the ends of the side pieces 4, and aids in centering the shank upon the chuck. The side. pieces 4 may also. be placed at selected positions on the end portion 2, in accordance with sizes and conditions, and form with said end portion a frnsto-conical shank. 1 I

The result is a drill of substantial form, made at approximately one-half the cost of an ordinary twist drill in which the flutes arc inilled" and which is capable of engagement in any ordinary socket.

Having thus fully described my invention, what I claim and desire to secure by Letters Patent is A twist drill having a strai ht flat sided shank or end portion and mcm ers arranged on opposite sides and secured upon an interme'thate portion thereof, said members being counterparts and of approximately semicircular eross section, having their curved faces of tapering out-line and forming with the said WILLIAM R. DOWN Witnesses En. A. KELLY, F. B. Wntnna. 

